Visually stunning but the writing was s***

I have rarely seen a movie that I enjoyed this much on a visual level. This is on par with "Gladiator" or "L.A. Confidential". Visually every aspect of this movie was a pleasure. From the color use (cold blue colors for the present day scenes, yellow/brown for the past and little plays of other colors in between to accentuate individual characters),
to the way individual scenes are shot (Young Cal running away across the half sunken pier with the crumbling buildings in the background, Cal standing on the garden wall over the city),
to the appearance of the characters (The subtle way that all templars were white while the assassins were a mix of people, Moussa's look with the white streaked beard),
to the set design, the fight choreography and the effects...every detail was perfect and stunning.

But the writing was horrible. Some conversations were just painful to get through. Every time they talked about violence I just wanted to reach into the screen and slap them. The fat guard talked to Cal as if he wanted to encourage him to rebel (I half expected him to be an assassin infiltrator at one point)...why? Why was Sofia so surprised that the Templars wanted to use the apple to control the world? I mean, the templars are not really shy about their intentions (Even if she did not share that goal, she had to know what the others wanted if she ever attended a meeting before). She lets Cal into the ballroom to kill her father and then swears revenge? What happened in the 30 seconds between those scenes that made her change her mind? The movie is full of that kind of things. There is one, only one, good line in the entire movie (the one about eating an apple).

How could anybody write something so bad? I felt terrible for the actors who were delivering such great performances with such a pile of garbage.